* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

li {
    list-style-type: none;
    margin: 30px 0;
    color:#fff;
}

body {
    background-color: #333;
}

.color {
    width: 100vw;
    height: 120vh;
    background-color: #fff;
    transform-origin: top left;
    transition: transform .5s ease-in;
}

.color.show {
    transform: rotate(-20deg);
}

.yuan {
    position: fixed;
    left: -100px;
    top: -100px;
    z-index: 1;
}

.btn {
    cursor: pointer;
    width: 200px;
    height: 200px;
    background-color: rgb(255, 53, 53);
    border-radius: 50%;
    position: relative;
    transition: transform .8s linear;
}

.btn>button {
    cursor: pointer;
    color: #fefefe;
    height: 100px;
    width: 80px;
    font-size: 40px;
    background-color: transparent;
    position: absolute;
    left: 50%;
    top: 50%;
    border: 0;
}

.close {
    transform: rotate(90deg);
    transform-origin: top left;
}

.btn.show {
    transform: rotate(-90deg);
    transition: transform .8s linear;
}

.icon {
    position: fixed;
    bottom: 30px;
    left: 0px;
    transform: translateX(-200%);
    transition: transform .8s linear;
}

.icon.show {
    transform: translateX(0%);
    transition: transform .8s linear;
}
ul li:nth-child(1) {
    font-size: 20px;
    margin-left: 20px;
}
ul li:nth-child(2) {
    font-size: 20px;
    margin-left: 40px;
}
ul li:nth-child(3) {
    font-size: 20px;
    margin-left: 60px;
}